A The present invention relates to a multi-colour rotary flexographic machine of the narrow-web type.
As it is known, replacement of the printing plate cylinder and the anilox roller in each printing unit of a conventional flexographic rotary machine is a troublesome operation which requires long machine downtimes.
The main object of the present invention is to provide a new flexographic rotary machine with separate printing units in which changing of printing and/or printing colours can be made in a quick and easy way.
Another object of the present invention is to provide a high performance flexographic rotary machine which is highly reliable and precise.
These and other objects which will become better apparent hereinafter are achieved by a flexographic rotary printing machine according to the invention, which comprises a supporting structure, an impression roller on which a sheet material to be printed passes, at least one printing unit arranged adjacent to said impression roller and having a closed-chamber doctor-blade inking group, a printing plate cylinder and an anilox roller, which are of sleeve cylinder type, motion transmission means between said impression roller and each printing assembly, and at least one lateral support device for forward and backward movements of said sleeve cylinders which is arranged to move them between a retracted or resting position, in which a respective sleeve can be inserted or removed, and an advanced or printing position, in which they are kept in contact with, and operatively connected to, said impression roller.
Advantageously, said lateral support device comprises at least one slide provided with recirculating ballscrew sliding blocks and a guide of antifriction material.